Static magnetic field-modulated mesenchymal stem cell-derived mitochondria-containing microvesicles for enhanced intervertebral disc degeneration therapy.

Intervertebral disc degeneration (IVDD) is characterized by the senescence and declining vitality of nucleus pulposus cells (NPCs), often driven by mitochondrial dysfunction. This study elucidates that mesenchymal stem cells (MSCs) play a crucial role in attenuating NPC senescence by secreting mitochondria-containing microvesicles (mitoMVs). Moreover, it demonstrates that static magnetic fields (SMF) enhance the secretion of mitoMVs by MSCs. By distinguishing mitoMV generation from exosomes, this study shifts focus to understanding the molecular mechanisms of SMF intervention, emphasizing cargo transport and plasma membrane budding processes, with RNA sequencing indicating the potential involvement of the microtubule-based transport protein Kif5b. The study further confirms the interaction between Rab22a and Kif5b, revealing Rab22a's role in sorting mitoMVs into microvesicles (MVs) and potentially mediating subsequent plasma membrane budding. Subsequent construction of a gelatin methacrylate (GelMA) hydrogel delivery system further addresses the challenges of in vivo application and verifies the substantial potential of mitoMVs in delaying IVDD. This research not only sheds light on the molecular intricacies of SMF-enhanced mitoMV secretion but also provides innovative perspectives for future IVDD therapeutic strategies.

Exosomal Lnc NEAT1 from endothelial cells promote bone regeneration by regulating macrophage polarization via DDX3X/NLRP3 axis.

BACKGROUND: Bone regeneration is a complex procedure that involves an interaction between osteogenesis and inflammation. Macrophages in the microenvironment are instrumental in bone metabolism. Amount evidence have revealed that exosomes transmitting lncRNA is crucial nanocarriers for cellular interactions in various biotic procedures, especially, osteogenesis. However, the underlying mechanisms of the regulatory relationship between the exosomes and macrophages are awaiting clarification. In the present time study, we aimed to explore the roles of human umbilical vein endothelial cells (HUVECs)-derived exosomes carrying nuclear enrichment enriched transcript 1 (NEAT1) in the osteogenesis mediated by M2 polarized macrophages and elucidate the underlying mechanisms. RESULTS: We demonstrated HUVECs-derived exosomes expressing NEAT1 significantly enhanced M2 polarization and attenuated LPS-induced inflammation in vitro. Besides, the conditioned medium from macrophages induced by the exosomes indirectly facilitated the migration and osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Mechanically, Exos carrying NEAT1 decreased remarkably both expression of dead-box helicase 3X-linked (DDX3X) and nod-like receptor protein 3 (NLRP3). The level of NLRP3 protein increased significantly after RAW264.7 cells transfected with DDX3X overexpression plasmid. Additionally, the knockdown of NEAT1 in exosomes partially counteracted the aforementioned effect of Exos. The results of air pouch rat model demonstrated that HUVECs-derived exosomes increased anti-inflammatory cytokines (IL-10) and decreased pro-inflammatory cytokines (IL-1ß and IL-6) significantly in vivo, contributing to amelioration of LPS-induced inflammation. Afterwards, we further confirmed that the HUVECs-derived exosomes encapsulated in alginate/gelatin methacrylate (GelMA) interpenetrating polymer network (IPN) hydrogels could promote the bone regeneration, facilitate the angiogenesis, increase the infiltration of M2 polarized macrophages as well as decrease NLRP3 expression in the rat calvarial defect model. CONCLUSIONS: HUVECs-derived exosomes enable transmitting NEAT1 to alleviate inflammation by inducing M2 polarization of macrophages through DDX3X/NLRP3 regulatory axis, which finally contributes to osteogenesis with the aid of alginate/GelMA IPN hydrogels in vivo. Thus, our study provides insights in bone healing with the aid of HUVECs-derived exosomes-encapsulated composite hydrogels, which exhibited potential towards the use of bone tissue engineering in the foreseeable future.

Active targeting schemes for nano-drug delivery systems in osteosarcoma therapeutics.

Osteosarcoma, the most common malignant tumor of the bone, seriously influences people's lives and increases their economic burden. Conventional chemotherapy drugs achieve limited therapeutic effects owing to poor targeting and severe systemic toxicity. Nanocarrier-based drug delivery systems can significantly enhance the utilization efficiency of chemotherapeutic drugs through targeting ligand modifications and reduce the occurrence of systemic adverse effects. A variety of ligand-modified nano-drug delivery systems have been developed for different targeting schemes. Here we review the biological characteristics and the main challenges of current drug therapy of OS, and further elaborate on different targeting schemes and ligand selection for nano-drug delivery systems of osteosarcoma, which may provide new horizons for the development of advanced targeted drug delivery systems in the future.

Vasorin-containing small extracellular vesicles retard intervertebral disc degeneration utilizing an injectable thermoresponsive delivery system.

Intervertebral disc degeneration (IDD) is the pathological reason of back pain and the therapeutic approaches are still unsatisfactory. Recently, mesenchymal stem cell-derived small extracellular vesicles (EVs) have emerged as the novel regenerative method for IDD. In this study, we intensively investigated the therapeutic mechanism of small EVs, and found that vasorin protein enriched in EVs promoted the proliferation and extracellular matrix anabolism of nucleus pulposus cells via the Notch1 signaling pathway. Then, we fabricated a thermoresponsive gel which composed of Pluronic F127 and decellularized extracellular matrix (FEC) for the delivery and sustained release of EVs. Besides, ex vivo and in vivo results showed that EVs embedded in FEC (EVs@FEC) ameliorate the disc degeneration efficiently and achieve better therapeutic effects than one-off EVs delivery. Collectively, these findings deepen the understanding of EVs mechanism in treating intervertebral disc degeneration, and also illustrate the promising capacity of sustained EVs release system for intervertebral disc regeneration.

RETREG1-mediated ER-phagy activation induced by glucose deprivation alleviates nucleus pulposus cell damage via ER stress pathway.

Accumulating evidence indicates that ER-phagy serves as a key adaptive regulatory mechanism in response to various stress conditions. However, the exact mechanisms underlying ER-phagy in the pathogenesis of intervertebral disc degeneration remain largely unclear. In the present study, we demonstrated that RETREG1-mediated ER-phagy is induced by glucose deprivation (GD) treatment, along with ER stress activation and cell function decline. Importantly, ER-phagy was shown to be crucial for cell survival under GD conditions. Furthermore, ER stress was suggested as an upstream event of ER-phagy upon GD treatment and upregulation of ER-phagy could counteract the ER stress response. Therefore, our findings indicate that RETREG1-mediated ER-phagy activation protects against GD treatment-induced cell injury via modulating ER stress in human nucleus pulposus cells.

The involvement of regulated in development and DNA damage response 1 (REDD1) in the pathogenesis of intervertebral disc degeneration.

Regulated in development and DNA damage response 1 (REDD1) is an evolutionarily conserved, ubiquitous protein that responds to various cell stresses. Studies have proved REDD1 is involved in many diseases, such as osteoarthritis and cancer. The present study aimed to investigate the potential role of REDD1 in the pathogenesis of intervertebral disc degeneration (IDD). Analysis of clinical tissue samples showed REDD1 expression was up-regulated during IDD and was correlated with the grade of disc degeneration. Overexpression of REDD1 in normal human nucleus pulposus (NP) cells resulted in extracellular matrix (ECM) degeneration. Further, we investigated the function of REDD1 using a serum deprivation-induced IDD vitro model and found that REDD1 was up-regulated in a temporal manner. However, hypoxia abolished this increase through down-regulation of NF-κB. Knockdown of REDD1 or NF-κB by si-RNA significantly rescued ECM from degeneration both in normoxia and hypoxia. In addition, NF-κB/REDD1 mediated the protection of hypoxia from serum deprivation-induced apoptosis and autophagy in NP cells. These results suggest that REDD1 might play a pivotal role in IDD pathogenesis, thereby potentially providing a new therapeutic target for IDD treatment.

Autophagy attenuates compression-induced apoptosis of human nucleus pulposus cells via MEK/ERK/NRF1/Atg7 signaling pathways during intervertebral disc degeneration.

Autophagy dysfunction has been observed in intervertebral disc degeneration (IVDD) cells, a main contributing factor to cell death, but the precise role of autophagy during IVDD is still controversial. This study aimed to investigate the role of autophagy involved in the pathogenesis of human IVDD and determine the signal transduction pathways responsible for compression-induced autophagy in human nucleus pulposus (NP) cells. Autophagy, suppressing the induction of apoptosis, was activated in NP cells exposed to compression. Molecular analysis showed that compression promoted the activity of NRF1, a transcription regulator increasing Atg7 expression by binding to its promoter, through activating the Ras/MEK/ERK signaling in NP cells. Loss- and gain-of-function studies demonstrate that NRF1 induced autophagy and dampened the apoptotic response by promoting Atg7 expression in NP cells subjected to compression. This study confirmed that compression-induced autophagy could be induced by Ras via MEK/ERK/NRF1/Atg7 signaling pathways, while inhibiting Ras/MEK/ERK/NRF1/Atg7 signaling pathways attenuated this autophagic process, implicating a promising therapeutic strategy for IVDD.

The noncoding RNA linc-ADAMTS5 cooperates with RREB1 to protect from intervertebral disc degeneration through inhibiting ADAMTS5 expression.

Previous studies have indicated the important roles of ADAMTS5 in intervertebral disc degeneration (IDD). However, the mechanisms that regulate ADAMTS5 expression in nuclear pulposus (NP) cells remain largely unknown. Evidence suggests that intergenic transcription may be associated with genes that encode transcriptional regulators. Here, we identified a long intergenic noncoding RNA, linc-ADAMTS5, which was transcribed in the opposite direction to ADAMTS5. In the present study, through mining computational algorithm programs, and publicly available data sets, we identified Ras-responsive element-binding protein 1 (RREB1) as a crucial transcription factor regulating the expression of ADAMTS5 in NP cells. RNA pull-down, RNA immunoprecipitation (RIP), in vitro binding assays, and gain- and loss-of-function studies indicated that a physical interaction between linc-ADAMTS5 and splicing factor proline/glutamine-rich (SFPQ) facilitated the recruitment of RREB1 to binding sites within the ADAMTS5 promoter to induce chromatin remodeling. This resulted in subdued ADAMTS5 levels in cultured NP cells involving histone deacetylases (HDACs). In clinical NP tissues, linc-ADAMTS5 and RREB1 were correlated negatively with ADAMTS5 expression. Taken together, these results demonstrate that RREB1 cooperates with noncoding RNA linc-ADAMTS5 to inhibit ADAMTS5 expression, thereby affecting degeneration of the extracellular matrix (ECM) of the intervertebral disc (IVD).

MicroRNA-15b silencing inhibits IL-1ß-induced extracellular matrix degradation by targeting SMAD3 in human nucleus pulposus cells.

OBJECTIVES: To determine the role of microRNA-15b (miR-15b) in interleukin-1 beta (IL-1ß)-induced extracellular matrix (ECM) degradation in the nucleus pulposus (NP). RESULTS: MiR-15b was up-regulated in degenerative NP tissues and in IL-1ß-stimulated NP cells, as compared to the levels in normal controls (normal tissue specimens from patients with idiopathic scoliosis). Bioinformatics and luciferase activity analyses showed that mothers against decapentaplegic homolog 3 (SMAD3), a key mediator of the transforming growth factor-ß signaling pathway, was directly targeted by miR-15b. Functional analysis demonstrated that miR-15b overexpression aggravated IL-1ß-induced ECM degradation in NP cells, while miR-15b inhibition had the opposite effects. Prevention of IL-1ß-induced NP ECM degeneration by the miR-15b inhibitor was attenuated by small-interfering-RNA-mediated knockdown of SMAD3. In addition, activation of MAP kinase and nuclear factor-κB up-regulated miR-15b expression and down-regulated SMAD3 expression in IL-1ß-stimulated NP cells. CONCLUSIONS: MiR-15b contributes to ECM degradation in intervertebral disc degeneration (IDD) via targeting of SMAD3, thus providing a novel therapeutic target for IDD treatment.

Investigation of the Relationship Between Flatfoot and Patellar Subluxation in Adolescents.

Patellar subluxation is common in adolescents, and a variety of factors are related to this condition, with valgus of the knee joint an important factor. The results of many studies suggest that flatfoot can cause an abnormality of the lower limb power line. Structural abnormalities of the foot caused by the high stresses exerted by body weight can lead to structural deformity of the knee and can also cause knee valgus. Screening for foot problems can help determine the risk of patellar subluxation, and early intervention can lessen the incidence of this condition. The purpose of the present study was to investigate the effects of flatfoot on the structure and function of the knees and, especially, the risk of patellar subluxation. A total of 72 participants were recruited for this cross-sectional study. The mean age at examination was 15.4 ± 4.0 (range 9 to 22) years. The measured parameters were heel valgus angle, arch index, and quadriceps angle (Q-angle). Overall, the mean values of the heel valgus angle, arch index, and Q-angle were 5.9° ± 2.4° (range 1° to 11°), 0.33 ± 0.07 (range 0.23 to 0.46), and 19.1° ± 3.5° (range 9° to 26°), respectively. The Q-angle was directly associated with the heel valgus angle (r = 0.818, p < .001) and arch index (r = 0.655, p < .001). We found that flatfoot can affect the morphology of the knee joint and increase the risk of patellar subluxation.

Minimally invasive posterior cervical foraminotomy versus anterior cervical fusion and arthroplasty: Systematic review and updated meta-analysis.

Introduction: This study is a systematic review and meta-analysis that investigates the efficacy of different surgical methods for treating cervical disc herniation or cervical foraminal stenosis. Research question: The research aimed to compare the efficacy of Minimally Invasive Posterior Cervical Foraminotomy (MI-PCF) with anterior approaches, namely Anterior Cervical Discectomy and Fusion (ACDF) and Cervical Disc Arthroplasty (CDA). Material and methods: The study included a comprehensive review of eight articles that compared ACDF and MI-PCF, and four articles that compared CDA to MI-PCF. Results: The results indicated no significant difference in surgical duration, hospital stay, complication rates, and reoperation rates between MI-PCF and ACDF. However, when comparing CDA with MI-PCF, it was found that CDA had a higher complication rate, while MI-PCF had a higher reoperation rate. Discussion and conclusion: Despite these findings, the study recommends MI-PCF as the preferred surgical method for cervical radiculopathy, owing to the advancements in minimally invasive techniques. However, these findings are preliminary, and further research with longer follow-up periods and larger sample sizes is necessary to confirm these findings and to further explore the potential advantages and disadvantages of these surgical methods.

Acute Neck Pain from Crowned Dens Syndrome: A Case Report and Clinical Insights.

BACKGROUND Crowned dens syndrome (CDS) is a rare condition characterized by deposition of calcium pyrophosphate crystals on the odontoid process of the second cervical vertebra, forming a calcified 'crown', with neck pain being a common symptom. The disorder exhibits unique clinical and radiological features, resembling manifestations of meningitis, such as acute headaches and cervical stiffness. There are few case reports and case series related to CDS. Patients generally respond well to treatment with nonsteroidal anti-inflammatory drugs (NSAIDs), although there is a certain rate of recurrence. Since there are few reports of CDS, we sought to publish this case report, aiming of increasing clinicians' awareness and reducing misdiagnosis rates. CASE REPORT A 62-year-old man presented to the Emergency Department with "cutting-like" headaches and neck pain for 2 days, and was subsequently diagnosed with CDS by cervical computed tomography (CT) scan, and hematological tests revealed inflammatory manifestations. He was advised to take oral nonsteroidal anti-inflammatory drugs and to rest; his symptoms improved after 3 days and his neck pain had almost resolved after 2 months. CONCLUSIONS In older patients experiencing new headaches and neck pain, along with increased inflammatory markers, particularly those with a history of pseudogout, the possibility of CDS should be considered. Case reports suggest that oral NSAIDs and short courses of corticosteroids can generally alleviate symptoms. Further research is needed on CDS diagnosis and treatment.

The role of oxidative stress in intervertebral disc degeneration: Mechanisms and therapeutic implications.

Oxidative stress is one of the main driving mechanisms of intervertebral disc degeneration(IDD). Oxidative stress has been associated with inflammation in the intervertebral disc, cellular senescence, autophagy, and epigenetics of intervertebral disc cells. It and the above pathological mechanisms are closely linked through the common hub reactive oxygen species(ROS), and promote each other in the process of disc degeneration and promote the development of the disease. This reveals the important role of oxidative stress in the process of IDD, and the importance and great potential of IDD therapy targeting oxidative stress. The efficacy of traditional therapy is unstable or cannot be maintained. In recent years, due to the rise of materials science, many bioactive functional materials have been applied in the treatment of IDD, and through the combination with traditional drugs, satisfactory efficacy has been achieved. At present, the research review of antioxidant bioactive materials in the treatment of IDD is not complete. Based on the existing studies, the mechanism of oxidative stress in IDD and the common antioxidant therapy were summarized in this paper, and the strategies based on emerging bioactive materials were reviewed.

A Janus-ROS Healing System Promoting Infectious Bone Regeneration via Sono-Epigenetic Modulation.

Elimination of bacterial infections and simultaneously promoting osteogenic differentiation are highly required for infectious bone diseases. Massive reactive oxygen species (ROS) can damage cells, while low ROS concentrations as a molecular signal can regulate cellular fate. In this study, a Janus-ROS healing system is developed for infectious bone regeneration. An alendronate (ALN)-mediated defective metal-organic framework (MOF) sonosensitizer is prepared, which can effectively clear Methicillin-resistant Staphylococcus aureus (MRSA) infections and promote osteogenic differentiation under differential ultrasonic irradiation. In the presence of zirconium-phosphate coordination, the ALN-mediated porphyrin-based MOF (HN25) with a proper defect has great sonodynamic antibacterial efficiency (98.97%, 15 min) and bone-targeting ability. Notably, under low-power ultrasound irradiation, HN25 can increase the chromatin accessibility of ossification-related genes and FOXO1 to promote bone repair through low ROS concentrations. Animal models of paravertebral infection, fracture with infection, and osteomyelitis demonstrate that HN25 successfully realizes the targeted and potent repair of various infectious bone tissues through rapid MRSA elimination, inhibiting osteoclast activity and promoting bone regeneration. The results show that high catalytic efficiency and bioactive MOF can be constructed using pharmaceutical-mediated defect engineering. The Janus-ROS treatment is also a promising therapeutic mode for infectious tissue regeneration.

Self-powered triboelectric-responsive microneedles with controllable release of optogenetically engineered extracellular vesicles for intervertebral disc degeneration repair.

Excessive exercise is an etiological factor of intervertebral disc degeneration (IVDD). Engineered extracellular vesicles (EVs) exhibit excellent therapeutic potential for disease-modifying treatments. Herein, we fabricate an exercise self-powered triboelectric-responsive microneedle (MN) assay with the sustainable release of optogenetically engineered EVs for IVDD repair. Mechanically, exercise promotes cytosolic DNA sensing-mediated inflammatory activation in senescent nucleus pulposus (NP) cells (the master cell population for IVD homeostasis maintenance), which accelerates IVDD. TREX1 serves as a crucial nuclease, and disassembly of TRAM1-TREX1 complex disrupts the subcellular localization of TREX1, triggering TREX1-dependent genomic DNA damage during NP cell senescence. Optogenetically engineered EVs deliver TRAM1 protein into senescent NP cells, which effectively reconstructs the elimination function of TREX1. Triboelectric nanogenerator (TENG) harvests mechanical energy and triggers the controllable release of engineered EVs. Notably, an optogenetically engineered EV-based targeting treatment strategy is used for the treatment of IVDD, showing promising clinical potential for the treatment of degeneration-associated disorders.

Disassembly of the TRIM56-ATR complex promotes cytoDNA/cGAS/STING axis-dependent intervertebral disc inflammatory degeneration.

As the leading cause of disability worldwide, low back pain (LBP) is recognized as a pivotal socioeconomic challenge to the aging population and is largely attributed to intervertebral disc degeneration (IVDD). Elastic nucleus pulposus (NP) tissue is essential for the maintenance of IVD structural and functional integrity. The accumulation of senescent NP cells with an inflammatory hypersecretory phenotype due to aging and other damaging factors is a distinctive hallmark of IVDD initiation and progression. In this study, we reveal a mechanism of IVDD progression in which aberrant genomic DNA damage promoted NP cell inflammatory senescence via activation of the cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) axis but not of absent in melanoma 2 (AIM2) inflammasome assembly. Ataxia-telangiectasia-mutated and Rad3-related protein (ATR) deficiency destroyed genomic integrity and led to cytosolic mislocalization of genomic DNA, which acted as a powerful driver of cGAS/STING axis-dependent inflammatory phenotype acquisition during NP cell senescence. Mechanistically, disassembly of the ATR-tripartite motif-containing 56 (ATR-TRIM56) complex with the enzymatic liberation of ubiquitin-specific peptidase 5 (USP5) and TRIM25 drove changes in ATR ubiquitination, with ATR switching from K63- to K48-linked modification, c thereby promoting ubiquitin-proteasome-dependent dynamic instability of ATR protein during NP cell senescence progression. Importantly, an engineered extracellular vesicle-based strategy for delivering ATR-overexpressing plasmid cargo efficiently diminished DNA damage-associated NP cell senescence and substantially mitigated IVDD progression, indicating promising targets and effective approaches to ameliorate the chronic pain and disabling effects of IVDD.

Hsa_circ_0001946 Ameliorates Mechanical Stress-induced Intervertebral Disk Degeneration Via Targeting miR-432-5p and SOX9.

STUDY DESIGN: Experimental analysis of circular RNA in intervertebral disk degeneration (IDD). OBJECTIVE: This study aimed to explore the roles of hsa_circ_0001946 (circ-CDR1as) in mechanical stress-induced nucleus pulposus cell injury in IDD. SUMMARY OF BACKGROUND DATA: Mechanical stress is an important pathogenic factor for IDD. Excessive compression stress leads to nucleus pulposus (NP) cell apoptosis and extracellular matrix (ECM) degradation and accelerated IDD. Circ-CDR1as is associated with various degenerative conditions, but its role in IDD is not clear. Herein, we explored the roles and mechanisms of circ-CDR1as in IDD in vitro. MATERIALS AND METHODS: An in vitro model of IDD was constructed by treating NP cells with 1.0 MPa compression stress. Quantitative real-time polymerase chain reaction assay was used for detecting the expression of circ-CDR1as and miR-432-5p. Immunofluorescent analysis was performed for MMP13 detection. Western blot assay was performed for detecting apoptosis and ECM-related protein expression. Flow cytometry analysis was used for cell apoptosis analysis. The dual-luciferase reporter was used to analyze the interaction between miR-432-5p and circ-CDR1as or SOX9. Differences in means between groups were evaluated using the Student t test or one-way analysis of variance. RESULTS: In compression-treated human NP cells, we found that circ-CDR1as was significantly downregulated. Functional experiments showed that circ-CDR1as overexpression reduced the compression-induced apoptosis and ECM degradation in NP cells. Further research indicated that circ-CDR1as could act as a molecular sponge for miR-432-5p, a miRNA that enhanced compression-induced damage of NP cells by inhibiting the expression of SOX9. The luciferase reporter experiments also showed that the mutual dialogue between circ-CDR1as and miR-432-5p regulated the expression of SOX9. CONCLUSIONS: Circ-CDR1as binds to miR-432-5p and plays a protective role in mitigating compression-induced NP cell apoptosis and ECM degradation by targeting SOX9. Circ-CDR1as may provide a novel therapeutic target for the clinical management of IDD in the future.

Oxidative stress-induced endothelial cells-derived exosomes accelerate skin flap survival through Lnc NEAT1-mediated promotion of endothelial progenitor cell function.

BACKGROUND: Flap transplantation is commonly used in reconstructive surgery. A prerequisite for skin flap survival is sufficient blood supply. However, such approaches remain unclear. This study aimed to explore the underlying mechanisms of exosomes derived from human umbilical vascular endothelial cells (HUVECs) exposed to oxidative stress on endothelial progenitor cells (EPCs) and their subsequent influence on the survival of skin flaps. METHODS: HUVECs were treated with various concentrations of H2O2 to establish an oxidative stress model. To investigate the effects of H2O2-HUVEC-Exos and HUVEC-Exos, Cell Counting Kit-8, tube formation, invasion assays, and quantitative real-time polymerase chain reaction (qRT-PCR) were performed in EPCs. Microarray analysis was used to reveal the differentially expressed long non-coding RNAs (lncRNAs) in the H2O2-HUVEC-Exos and HUVEC-Exos. In addition, gene silencing and western blotting were employed to determine the mechanism behind lncRNA nuclear enrichment enriched transcript 1 (Lnc NEAT1) in EPCs. Further, a rat skin flap model was used to determine the role of the exosomes in skin flap survival in vivo. RESULTS: HUVECs were stimulated with 100 µmol/L H2O2 for 12 h to establish an oxidative stress model. H2O2-HUVEC-Exos promoted the proliferation, tube formation, and invasion of EPCs and remarkably increased skin flap survival compared to the HUVEC-Exos and control groups. Sequencing of exosome RNAs revealed that the Lnc NEAT1 level was dramatically increased in the H2O2-HUVEC-Exos, leading to activation of the Wnt/ß-catenin signaling pathway. Comparatively, knockdown of Lnc NEAT1 in HUVEC-Exos and H2O2-HUVEC-Exos significantly inhibits the angiogenic capacity of EPCs, reduced the survival area of skin flap and downregulated the expression levels of Wnt/ß-catenin signaling pathway proteins, whereas Wnt agonist partly reversed the negative effect of NEAT1 downregulation on EPCs through the Wnt/ß-catenin signaling pathway. CONCLUSIONS: Exosomes derived from HUVECs stimulated by oxidative stress significantly promoted the pro-angiogenic ability of EPCs through the Wnt/ß-catenin signaling pathway mediated by Lnc NEAT1 and hence enhanced random flap survival in vivo. Therefore, the application of H2O2-HUVEC-Exos may serve as an alternative therapy for improving random skin flap survival.

Therapeutic perspectives of exosomes in glucocorticoid-induced osteoarthrosis.

Exosomes are widely involved in a variety of physiological and pathological processes. These important roles are also hidden in the physiological processes related to bone. Chondrocytes, osteoblasts, synovial fibroblasts, and bone marrow mesenchymal stem cells produce and secrete exosomes, thereby affecting the biology process of target cells. Furthermore, in the primary pathogenesis of osteoarthrosis induced by steroid hormones, mainly involve glucocorticoid (GC), the exosomes have also widely participated. Therefore, exosomes may also play an important role in glucocorticoid-induced osteoarthrosis and serve as a promising treatment for early intervention of osteoarthrosis in addition to playing a regulatory role in malignant tumors. This review summarizes the previous results on this direction, systematically combs the role and therapeutic potential of exosomes in GC-induced osteoarthrosis, discusses the potential role of exosomes in the treatment and prevention of GC-induced osteoarthrosis, and reveals the current challenges we confronted.

Cytosolic escape of mitochondrial DNA triggers cGAS-STING-NLRP3 axis-dependent nucleus pulposus cell pyroptosis.

Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.